This patch removes the need for the offset parameter in dma bounce functions. This is required to let dma-mapping framework on ARM architecture to use common, generic dma_map_ops based dma-mapping helpers.
Background and more detailed explaination:
dma_*_range_* functions are available from the early days of the dma mapping api. They are the correct way of doing a partial syncs on the buffer (usually used by the network device drivers). This patch changes only the internal implementation of the dma bounce functions to let them tunnel through dma_map_ops structure. The driver api stays unchanged, so driver are obliged to call dma_*_range_* functions to keep code clean and easy to understand.
The only drawback from this patch is reduced detection of the dma api abuse. Let us consider the following code:
dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE); dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);
Without the patch such code fails, because dma bounce code is unable to find the bounce buffer for the given dma_address. After the patch the above sync call will be equivalent to:
dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);
which succeeds.
I don't consider this as a real problem, because DMA API abuse should be caught by debug_dma_* function family. This patch lets us to simplify the internal low-level implementation without chaning the driver visible API.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Acked-by: Kyungmin Park kyungmin.park@samsung.com Tested-By: Subash Patel subash.ramaswamy@linaro.org --- arch/arm/common/dmabounce.c | 13 +++++-- arch/arm/include/asm/dma-mapping.h | 67 ++++++++++++++++++------------------ arch/arm/mm/dma-mapping.c | 4 +-- 3 files changed, 45 insertions(+), 39 deletions(-)
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c index 210ad1b..32e9cc6 100644 --- a/arch/arm/common/dmabounce.c +++ b/arch/arm/common/dmabounce.c @@ -173,7 +173,8 @@ find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_ read_lock_irqsave(&device_info->lock, flags);
list_for_each_entry(b, &device_info->safe_buffers, node) - if (b->safe_dma_addr == safe_dma_addr) { + if (b->safe_dma_addr <= safe_dma_addr && + b->safe_dma_addr + b->size > safe_dma_addr) { rb = b; break; } @@ -362,9 +363,10 @@ void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size, EXPORT_SYMBOL(__dma_unmap_page);
int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr, - unsigned long off, size_t sz, enum dma_data_direction dir) + size_t sz, enum dma_data_direction dir) { struct safe_buffer *buf; + unsigned long off;
dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n", __func__, addr, off, sz, dir); @@ -373,6 +375,8 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr, if (!buf) return 1;
+ off = addr - buf->safe_dma_addr; + BUG_ON(buf->direction != dir);
dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n", @@ -391,9 +395,10 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr, EXPORT_SYMBOL(dmabounce_sync_for_cpu);
int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr, - unsigned long off, size_t sz, enum dma_data_direction dir) + size_t sz, enum dma_data_direction dir) { struct safe_buffer *buf; + unsigned long off;
dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n", __func__, addr, off, sz, dir); @@ -402,6 +407,8 @@ int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr, if (!buf) return 1;
+ off = addr - buf->safe_dma_addr; + BUG_ON(buf->direction != dir);
dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n", diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index 6a838da..eeddbe2 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -266,19 +266,17 @@ extern void __dma_unmap_page(struct device *, dma_addr_t, size_t, /* * Private functions */ -int dmabounce_sync_for_cpu(struct device *, dma_addr_t, unsigned long, - size_t, enum dma_data_direction); -int dmabounce_sync_for_device(struct device *, dma_addr_t, unsigned long, - size_t, enum dma_data_direction); +int dmabounce_sync_for_cpu(struct device *, dma_addr_t, size_t, enum dma_data_direction); +int dmabounce_sync_for_device(struct device *, dma_addr_t, size_t, enum dma_data_direction); #else static inline int dmabounce_sync_for_cpu(struct device *d, dma_addr_t addr, - unsigned long offset, size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir) { return 1; }
static inline int dmabounce_sync_for_device(struct device *d, dma_addr_t addr, - unsigned long offset, size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir) { return 1; } @@ -401,6 +399,33 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t handle, __dma_unmap_page(dev, handle, size, dir); }
+ +static inline void dma_sync_single_for_cpu(struct device *dev, + dma_addr_t handle, size_t size, enum dma_data_direction dir) +{ + BUG_ON(!valid_dma_direction(dir)); + + debug_dma_sync_single_for_cpu(dev, handle, size, dir); + + if (!dmabounce_sync_for_cpu(dev, handle, size, dir)) + return; + + __dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir); +} + +static inline void dma_sync_single_for_device(struct device *dev, + dma_addr_t handle, size_t size, enum dma_data_direction dir) +{ + BUG_ON(!valid_dma_direction(dir)); + + debug_dma_sync_single_for_device(dev, handle, size, dir); + + if (!dmabounce_sync_for_device(dev, handle, size, dir)) + return; + + __dma_single_cpu_to_dev(dma_to_virt(dev, handle), size, dir); +} + /** * dma_sync_single_range_for_cpu * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices @@ -423,40 +448,14 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir) { - BUG_ON(!valid_dma_direction(dir)); - - debug_dma_sync_single_for_cpu(dev, handle + offset, size, dir); - - if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir)) - return; - - __dma_single_dev_to_cpu(dma_to_virt(dev, handle) + offset, size, dir); + dma_sync_single_for_cpu(dev, handle + offset, size, dir); }
static inline void dma_sync_single_range_for_device(struct device *dev, dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir) { - BUG_ON(!valid_dma_direction(dir)); - - debug_dma_sync_single_for_device(dev, handle + offset, size, dir); - - if (!dmabounce_sync_for_device(dev, handle, offset, size, dir)) - return; - - __dma_single_cpu_to_dev(dma_to_virt(dev, handle) + offset, size, dir); -} - -static inline void dma_sync_single_for_cpu(struct device *dev, - dma_addr_t handle, size_t size, enum dma_data_direction dir) -{ - dma_sync_single_range_for_cpu(dev, handle, 0, size, dir); -} - -static inline void dma_sync_single_for_device(struct device *dev, - dma_addr_t handle, size_t size, enum dma_data_direction dir) -{ - dma_sync_single_range_for_device(dev, handle, 0, size, dir); + dma_sync_single_for_device(dev, handle + offset, size, dir); }
/* diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index e4ac5fc..a16993a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -660,7 +660,7 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int i;
for_each_sg(sg, s, nents, i) { - if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0, + if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), sg_dma_len(s), dir)) continue;
@@ -686,7 +686,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int i;
for_each_sg(sg, s, nents, i) { - if (!dmabounce_sync_for_device(dev, sg_dma_address(s), 0, + if (!dmabounce_sync_for_device(dev, sg_dma_address(s), sg_dma_len(s), dir)) continue;